Sunday, September 27, 2009

Power Usage Logging with the WELserver

Reading some forums about ground source heat pump installations, we noticed references to a logging system called the Web Energy Logger that collects data in your house and provides you with a detailed and customized view of how the systems in your house are operating. I bought a WELserver kit and have started installing some of the data collectors.

Simply put, the Web Energy Logger (or WEL) is the most economical way to monitor lots of temperature sensors, and a host of other energy related devices in your home or office. It's ideal to verify the performance or a solar thermal system, or to calculate the efficiency of a geothermal installation, or even to prove that your home really is Net Zero. Not only does the WEL give you a window into your energy environment, but it also provides a live snapshot and a range of trend charts that you can share on the WEB in real-time. Finally, the WEL records all your sensor data in monthly log files that are easy to download and import into programs like Excel. It's compact, versatile, and extremely configurable.

The minimal WEL in a Box is ideal for a DIY'er, and costs $375. In contrast, the more complete WEL Starter Kit is ready to run out-of-the-box with 10 temperature sensors and costs $525. All WEL's come with full monitoring software on the board, and a dedicated WEL logging site included in the price.

The monitors are all strung together in a daisy-chain configuration on a single twisted pair wire using the Dallas 1-Wire signaling technology. I got one of the optional current sensors and installed it in the electric hot water tank. Here is the sensor, one of the power wires needs to be threaded through the hole so it can detect current flow.

Here is the water tank. The orange wire had been installed without its protective shielding, so when that was fitted, we took the opportunity to add the sensor.

The recess in the top of the water tank has enough space to hold the sensor, with the black wire threaded through the hole.

The cover is in two parts, which gives easy access to the wiring again if needed.

At this point, I don't have the WEL configured. I need to add temperature sensors to the water pipes, and work out how to monitor the heat pump once we get it installed in place of the propane furnace. The WEL control box has an ethernet connection, and I'm not sure whether to run ethernet into the basement, or run the 1-wire cable around the house to monitor all the rooms. Spare wires in the existing telephone cabling can be used for this purpose.